panic: Data modified on freelist: word 4 of object 0xffff800000a35000 size 0x108 previous type free (0x0 != 0xdeafbead) Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *235235 43147 0 0 0x4000000 0 syz-executor.1 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821ccc21) at panic+0x15c sys/kern/subr_prf.c:207 malloc(108,2,a) at malloc+0xa23 sys/kern/kern_malloc.c:331 bpfopen(31700,1,2000,ffff80001d35ed58) at bpfopen+0xb5 sys/net/bpf.c:370 spec_open_clone(ffff80001d428188) at spec_open_clone+0x241 sys/kern/spec_vnops.c:748 spec_open(ffff80001d428188) at spec_open+0x40e VOP_OPEN(fffffd805e5ff0d0,1,fffffd806c3bfae0,ffff80001d35ed58) at VOP_OPEN+0x6a sys/kern/vfs_vops.c:153 vn_open(ffff80001d4283d8,1,0) at vn_open+0x490 sys/kern/vfs_vnops.c:183 doopenat(ffff80001d35ed58,ffffff9c,20000300,0,0,ffff80001d4285d0) at doopenat+0x28b sys/kern/vfs_syscalls.c:1148 syscall(ffff80001d428650) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3b6bb6f0a10, count: 4 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs. ddb> ddb> set $lines = 0 ddb> set $maxwidth = 0 ddb> show panic Data modified on freelist: word 4 of object 0xffff800000a35000 size 0x108 previous type free (0x0 != 0xdeafbead) ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff821ccc21) at panic+0x15c sys/kern/subr_prf.c:207 malloc(108,2,a) at malloc+0xa23 sys/kern/kern_malloc.c:331 bpfopen(31700,1,2000,ffff80001d35ed58) at bpfopen+0xb5 sys/net/bpf.c:370 spec_open_clone(ffff80001d428188) at spec_open_clone+0x241 sys/kern/spec_vnops.c:748 spec_open(ffff80001d428188) at spec_open+0x40e VOP_OPEN(fffffd805e5ff0d0,1,fffffd806c3bfae0,ffff80001d35ed58) at VOP_OPEN+0x6a sys/kern/vfs_vops.c:153 vn_open(ffff80001d4283d8,1,0) at vn_open+0x490 sys/kern/vfs_vnops.c:183 doopenat(ffff80001d35ed58,ffffff9c,20000300,0,0,ffff80001d4285d0) at doopenat+0x28b sys/kern/vfs_syscalls.c:1148 syscall(ffff80001d428650) at syscall+0x507 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3b6bb6f0a10, count: -11 ddb> show registers rdi 0xffffffff820a25a7 db_enter+0x17 rsi 0x821d __ALIGN_SIZE+0x721d rbp 0xffff80001d427e90 rbx 0xffff80001d427f40 rdx 0x821e __ALIGN_SIZE+0x721e rcx 0xffff80001d431000 rax 0xffff80001d431000 r8 0xffff80001d427e50 r9 0x1 r10 0xffff8000009f3280 r11 0x9231ab20e3757a8e r12 0x3000000008 r13 0xffff80001d427ea0 r14 0x100 r15 0x1 rip 0xffffffff820a25a8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80001d427e80 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=235235 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=55, nice=20 forw=0xffffffffffffffff, list=0xffff80001d35deb8,0xffffffff825ac710 process=0xffff8000ffffa010 user=0xffff80001d423000, vmspace=0xfffffd8056650aa8 estcpu=10, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 43147 45035 45079 0 2 0 syz-executor.1 *43147 235235 45079 0 7 0x4000000 syz-executor.1 96769 336248 0 0 3 0x14200 acct acct 66861 181423 0 0 3 0x14200 bored sosplice 43435 476779 82660 0 3 0x2 biowait syz-executor.0 45079 111176 82660 0 3 0x82 nanosleep syz-executor.1 82660 277562 51649 0 3 0x82 thrsleep syz-fuzzer 82660 435547 51649 0 3 0x4000082 nanosleep syz-fuzzer 82660 10779 51649 0 3 0x4000082 thrsleep syz-fuzzer 82660 428442 51649 0 3 0x4000082 thrsleep syz-fuzzer 82660 299192 51649 0 3 0x4000082 kqread syz-fuzzer 82660 56589 51649 0 3 0x4000082 thrsleep syz-fuzzer 82660 186508 51649 0 3 0x4000082 thrsleep syz-fuzzer 51649 49850 5741 0 3 0x10008a pause ksh 5741 248385 10660 0 3 0x92 select sshd 74212 448225 1 0 3 0x100083 ttyin getty 10660 12168 1 0 3 0x80 select sshd 58686 366953 18678 73 3 0x100090 kqread syslogd 18678 335793 1 0 3 0x100082 netio syslogd 48754 364410 1 77 3 0x100090 poll dhclient 4707 141971 1 0 3 0x80 poll dhclient 87003 138914 0 0 3 0x14200 bored smr 20736 45144 0 0 2 0x14200 zerothread 69100 480342 0 0 3 0x14200 aiodoned aiodoned 80120 358148 0 0 3 0x14200 syncer update 5892 35129 0 0 3 0x14200 cleaner cleaner 21520 308089 0 0 3 0x14200 reaper reaper 58346 362739 0 0 3 0x14200 pgdaemon pagedaemon 53885 233325 0 0 3 0x14200 bored crynlk 89591 239002 0 0 3 0x14200 bored crypto 15481 167729 0 0 3 0x40014200 acpi0 acpi0 96735 197575 0 0 3 0x14200 bored softnet 77002 389052 0 0 3 0x14200 bored systqmp 67698 69918 0 0 3 0x14200 bored systq 49860 335713 0 0 3 0x40014200 bored softclock 5506 449806 0 0 3 0x40014200 idle0 1 224828 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb> show all locks No such command ddb> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9471 6395K 6912K 78643K 10689 0 pcb 13 8K 8K 78643K 43 0 rtable 102 3K 3K 78643K 216 0 ifaddr 51 11K 12K 78643K 63 0 counters 21 16K 16K 78643K 21 0 ioctlops 0 0K 2K 78643K 21 0 iov 0 0K 12K 78643K 12 0 mount 1 1K 1K 78643K 1 0 vnodes 1221 77K 77K 78643K 1264 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 3 0 VM map 2 0K 0K 78643K 2 0 sem 12 1K 1K 78643K 20 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1794 195K 288K 78643K 12646 0 file desc 5 13K 25K 78643K 110 0 sigio 0 0K 0K 78643K 9 0 proc 49 38K 63K 78643K 369 0 subproc 32 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 115 0 in_multi 42 2K 2K 78643K 70 0 ether_multi 1 0K 0K 78643K 9 0 mrt 0 0K 0K 78643K 1 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 43 201K 201K 78643K 43 0 exec 0 0K 1K 78643K 183 0 pagedep 1 8K 8K 78643K 1 0 inodedep 1 32K 32K 78643K 1 0 newblk 1 0K 0K 78643K 1 0 VM swap 7 26K 26K 78643K 7 0 UVM amap 101 37K 38K 78643K 1098 0 UVM aobj 7 4K 4K 78643K 7 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 24 0 NDP 8 0K 0K 78643K 12 0 temp 82 3010K 3074K 78643K 4372 0 kqueue 3 4K 14K 78643K 18 0 SYN cache 2 16K 16K 78643K 2 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 6 0 0 1 0 1 1 0 8 0 rtpcb 80 25 0 23 1 0 1 1 0 8 0 rtentry 112 49 0 8 2 0 2 2 0 8 0 unpcb 120 111 0 103 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 239 0 239 1 1 0 1 0 8 0 tcpcb 544 168 0 164 2 0 2 2 0 8 1 ipq 40 2 0 2 1 0 1 1 0 8 1 ipqe 40 90 0 90 1 0 1 1 0 8 1 inpcb 280 316 0 309 2 0 2 2 0 8 1 nd6 48 7 0 3 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 212 0 40 13 0 13 13 0 8 0 art_table 32 213 0 40 2 0 2 2 0 8 0 art_node 16 48 0 10 1 0 1 1 0 8 0 sysvmsgpl 40 6 0 3 1 0 1 1 0 8 0 semupl 112 1 0 1 1 0 1 1 0 8 1 semapl 112 14 0 4 1 0 1 1 0 8 0 shmpl 112 5 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1539 0 139 46 0 46 46 0 8 0 ffsino 240 1539 0 139 83 0 83 83 0 8 0 nchpl 144 1880 0 270 60 0 60 60 0 8 0 uvmvnodes 72 1608 0 0 30 0 30 30 0 8 0 vnodes 208 1608 0 0 85 0 85 85 0 8 0 namei 1024 4730 0 4730 1 0 1 1 0 8 1 vcpupl 1984 1 0 0 1 0 1 1 0 8 0 vmpool 528 1 0 0 1 0 1 1 0 8 0 scsiplug 64 1 0 1 1 0 1 1 0 8 1 scxspl 192 5787 0 5786 1 0 1 1 0 8 0 plimitpl 152 15 0 8 1 0 1 1 0 8 0 sigapl 424 298 0 268 4 0 4 4 0 8 0 futexpl 56 2818 0 2818 1 0 1 1 0 8 1 knotepl 112 69 0 50 1 0 1 1 0 8 0 kqueuepl 144 52 0 50 1 0 1 1 0 8 0 pipelkpl 16 95 0 85 1 0 1 1 0 8 0 pipepl 120 190 0 171 1 0 1 1 0 8 0 fdescpl 432 282 0 268 2 0 2 2 0 8 0 filepl 120 1873 0 1775 4 0 4 4 0 8 1 lockfpl 104 41 0 40 1 0 1 1 0 8 0 lockfspl 48 15 0 14 1 0 1 1 0 8 0 sessionpl 112 17 0 7 1 0 1 1 0 8 0 pgrppl 48 17 0 7 1 0 1 1 0 8 0 ucredpl 96 150 0 143 1 0 1 1 0 8 0 zombiepl 144 268 0 268 1 0 1 1 0 8 1 processpl 896 298 0 268 4 0 4 4 0 8 0 procpl 624 407 0 370 4 0 4 4 0 8 0 sosppl 128 2 0 2 1 0 1 1 0 8 1 sockpl 400 456 0 439 4 0 4 4 0 8 2 mcl64k 65536 14 0 11 1 0 1 1 0 8 0 mcl16k 16384 3 0 3 1 0 1 1 0 8 1 mcl12k 12288 2 0 2 1 0 1 1 0 8 1 mcl9k 9216 3 0 3 1 0 1 1 0 8 1 mcl8k 8192 4 0 4 1 0 1 1 0 8 1 mcl4k 4096 19 0 19 2 1 1 1 0 8 1 mcl2k 2048 65609 0 65556 17 3 14 15 0 8 7 mtagpl 80 6 0 2 2 1 1 1 0 8 0 mbufpl 256 111191 0 110791 44 15 29 30 0 8 0 bufpl 280 4337 0 157 299 0 299 299 0 8 0 anonpl 16 54762 0 38523 97 2 95 95 0 107 28 amapchunkpl 152 2122 0 1987 20 0 20 20 0 158 13 amappl16 192 1958 0 1068 68 15 53 66 0 8 8 amappl15 184 3 0 1 1 0 1 1 0 8 0 amappl14 176 6 0 3 2 1 1 1 0 8 0 amappl13 168 31 0 29 1 0 1 1 0 8 0 amappl12 160 8 0 8 1 1 0 1 0 8 0 amappl11 152 64 0 52 1 0 1 1 0 8 0 amappl10 144 92 0 84 1 0 1 1 0 8 0 amappl9 136 377 0 374 1 0 1 1 0 8 0 amappl8 128 275 0 255 1 0 1 1 0 8 0 amappl7 120 181 0 169 1 0 1 1 0 8 0 amappl6 112 23 0 20 1 0 1 1 0 8 0 amappl5 104 220 0 209 1 0 1 1 0 8 0 amappl4 96 437 0 409 1 0 1 1 0 8 0 amappl3 88 115 0 108 1 0 1 1 0 8 0 amappl2 80 1455 0 1393 3 1 2 3 0 8 0 amappl1 72 14725 0 14311 27 17 10 20 0 8 0 amappl 80 641 0 598 2 0 2 2 0 84 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 253 0 253 1 1 0 1 0 8 0 dma64 64 6 0 6 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 64 6 0 0 1 0 1 1 0 8 0 uaddrrnd 24 283 0 268 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 283 0 268 1 0 1 1 0 8 0 vmmpekpl 168 6092 0 6066 2 0 2 2 0 8 0 vmmpepl 168 41750 0 39800 117 8 109 109 0 357 23 vmsppl 272 282 0 268 2 0 2 2 0 8 0 pdppl 4096 572 0 537 6 0 6 6 0 8 1 pvpl 32 155562 0 136361 220 0 220 220 0 265 64 pmappl 200 282 0 268 1 0 1 1 0 8 0 extentpl 40 46 0 29 1 0 1 1 0 8 0 phpool 112 187 0 21 5 0 5 5 0 8 0